Device for timing and adjusting balance wheel assemblies



Oct. 14, 1952 NEMENYI-KATZ DEVICE FOR TIMING AND ADJUSTING BALANCE WHEELASSEMBLIES Filed. NOV. 50, 1949 2 SHEETSSHEET l T/MA: 5256'. \R

snmr BY PELHY J).

.B. OPER/J TES RELAY AMPLIFIER THME BASE v GENERATOR CONTROL SWITCH Oct.14, 1952 L. NEMENYl-KATZ 2,613,529

DEVICE FOR TIMING AND ADJUSTING BALANCE WHEEL ASSEMBLIES Filed NOV. 30,1949 ELEcrmc MOTOR 2 SHEETS-Sl-IEET 2 AMPLIFIER CONTROL SWITCH PatentedOct. 14, 1952 (STATES PATEN M cs I DEVICE FOR 'rn'v'nNG AND ADJUSTING iALANQEIWH AS EMBL E v Laszlo Nemenyl-Katz, London, England a ApplicationNovember 30, 1'949,"seriai1-r61130,1os M Qreat'Britam November- 30, 1948"1 Claim. (or. 73- 6) t w I This invention'relates in general to an apparatus for th'e timing of clocks and" watches and the like andmore-particularly 'toappara'tusdor the timing and adjustment-of balancewheeland hairspring assemblies of clocks and watches;

Inythemanufacture"ofclocksandwatches each balance 'wheeltwithitsassociated hairspr ing undergoes"a preliminary tirnln adjustmentbefore 'installation 'in the clock or watch" of which it isto"-fo'rinpart' in'l order to' lnsure that the frequency ofoScillatidhis withifi'the limits of regulation provided in thecompletedmovementi The correct rate of'oscil1ation i's' commonly securedduring such preliminary timing'adjustinent by gradually-decreasing thelength of the hairspring until' the wh'eeloscn ate afithe desiredpredetermined *frequencyifor the movement concerned. -"KnWnf-afiparatu6feiipeditifigthis preliminary timing operationmaYbeclassified into twomain types -m aeceraafice witn =the bas1 principles employed. I

In one main type 'of known apparatus the operation or timing-isbas'ed onthe principle that in an oscilla'tdry -systernf the am'plitude oi?oscillations builds u'p teiarge inagnitudesas the resonant frequencyofjthe 's'ystem is brought into type of knowfiappa'ratus the wheel"under test is constrained to:executeforcedoscillations under theinfluence of ahd 'lit the" same frequency as a driving force ofstandard'predetermined frequency while the hairsp'ring length is being adju'stedto the point :atiiiwhich" the amplitude of thePwheelT-attains to amaximum second:main type ofknown apparatus is that the wheel is allowed1 to executefree oscillations the frequencyofrwhich is compared-with astandard"predetermined frequency while the hairspring undergoesadjustmentgtojthe point atwhichthe free oscillations executedhby; the'lwheel-become' equal in rrequenoy-to'that of the said standardfrequencyj I '1- l The-present invention relates to an apparatus of thisSBCOndtYDGf; namely that in which the wheel executes free oscillationsthe frequency (ifwhich is comparedwith that' of: a standardpredetermined source. 1, ,f According to the present invention thebalance wheel under test isfautomaticallymaintained in a state'ofcontinuous orfsustafinedseli' oscillation throughout the adjustment,process." This situationis' exactly analogo s tof'the' case'ot'a'n'electrica'l self osoilIatorf'irr" whi dhjh frequency of il n rreen brie.;1 %s nsene*r h According tofthe" invention the system, is varied byadjustment or one of the said constants. By means known in' theart-adapted to'respo'nd to the-movement's ofthe balancewheel sharpelectrical impulses are -generated having a frequency equal to thefrequency of self-oscillation or" the wheel; -'I-'hese=sharp impu1ses;hereiiiafte'r' referred to as-wheel-pulsesfl" areapplied "according tothe invention-to control the operation ofan electrical" time-basegenerator 'of sta'nda'rd" predetermined period in' such manner 3 that atime-base is initiated at-th'einstant-of arrival ofeach wheel pulse, thesaid time-=base terminatlng after the'flapse 'o'i' the' said standardperiod. At the'instant oft'ermination or Leach time-base-period a. sharpimpulse is emitted by the'time-base generator. -'This latter sh'arpimpulse emitted by; the time -base generator at v the termination ofeach standard time-base interval hereinafter referred toas a -standardpulse." It will be appreoiated'from the foregoing explanation that whenthe s elf-oscillatory :period of a wheel 'is longer slow) than thestandard time-base, a standard -pulse will be emitted before thegeneration =0f the succeeding wheel-pulse initiating the next standardtime-base. Conse- 'quently' there will be an interval of time betweenthe standard pulse and thesucceeding wheelpulseand this intervalconstitutes at any-moment during the timing process,-a;- measure" ofthediscrepancy between th'e'p'e'riod of self -oscillation of the wheeland the-standard predetermined period ot'the wheel controlled time-basegenerator, which standard period the wheel should eventually-reach Itwill-be evident also-that when the wheel reaches the condition 'ofcorre'ct timing the wheel-pulses will becoincident exactly with thestandard-pulses. a said standardpuls'es and wheel pulses 'are employedto control 'thestarting and stopping;- respectively, of "anelectr'icmotor suitably coupled mechanically I to the 'hairspring' withthe object of accomplishing quisi'te progressive shortening of th'ehair-"spring, 1

-' Fromthe manner in which the standard pulses and wheel-pulse"s"arederived it Will be understood that the time interval ifor' which thesaid shortening""r'riotor is operative is 'g'o'vern'e'd by the duration"of the discrepancy interval between-the standardpulsesand thewheel-pulses. l Le'tI us assume for example thatthe' balance wheel hasto be adjusted to oscillate with a required-natural period-of 500'milliseconds. The said period for 500- milliseconds will ther' e'fore'bathe predetermin'ed" standard -p'eriod of the time base generator-L"Now suppose that during s'omepo'intof the timing adjustment the wheelissew-oscillating 'with "akperiod of 52 millisecon'd'si" assumedconditionsthe-standard 'timemaseg initiated by a when-pulse,'wnitermmat 500Ihilli- Under these Fig. 4 shows diagrammatically an pulse. There willthus be a discrepancy interval of milliseconds, during which. thehairspring shortening motor will be operative. As aconsequence of thisshortening the succeeding oscillation will tend to have a period'ofshorter duration and since the shorteningmotor isunder the control ofthe discrepancy interval'thecondi I.

tions established are such as will lead to a progressive diminution ofthe discrepancy interval. These conditions are therefore such that thesystern is varied-automatically towards the point of correct timing ofthe wheel.- 1

In practice the hairsprings are always made too long, for obviousreasons, and the d eg'ree of shorteningrequired may amount to. aconsiderable portion of the unadjusted spring. As a consequence muchtime may be consumed in a timing apparatus in. bringing the spring towithin close range of the correct length and this represents a'largeaddition to the manufacturing costs. Inthecase of the present inventionit will be: clear from the foregoing description of the principle underwhich the shortening motor operates that the springwill be rapidlybrought to within close range of the correct length since the amount ofshortening in each period is governed by the duration of the discrepancyinterval thereby giving-vastly improved type of operation.

To enable the invention to be more fully understood, it will now bedescribed with reference to the accompanying drawings-in which:

.Fig. l showsa balance-wheeland hair-spring assembly together, with thefine adjustment device in known clock and like mechanisms;

Fig. 2 shows graphically the oscillation of a balance wheel andhair-spring assembly and those of'a constant time base; i

Fig. 3 showsa balance wheel and hair-spring assembly mounted in a jigfor adjustment according to the invention;v

Referring to Fig. 1 a clockor like escapement mechanism includes abalance wheel l0 (not shown in Fig. lsee Fig. 3)-secured to a shaft l2and a hair-spring E4; the latter is securedto apparatus 22 whichembraces the spring [4 near the slot or the like. If the arm l8 is movedto the Fast side 'of 'the' scale 21 the extension 22'wi1l engage thespring M further from the slot; if moved to the Slow side it will engagethe spring nearer the slot thus the wheel will oscillate faster orslower owing to the' effective shortening or lengthening of the springl4. By this means a timed watch can be varied byup to 5 minutes eitherfast or slow per ,day., If a greater variation is required thespringmust be lengthened 0r shortened at the slot and therefore whencalibrating the spring l iwith'itsbalance wheel l0 during manufacture ofthe watch, its length must be determined so that when inserted in theclock or like mecha nism, with the forked extension in the centre of thescaleZi, the balance wheel and hair-spring assembly; will be adjusted tothis degree of accuracy. Q. I i

For this-purpose-according to the invention the balance wheel andhair-spring assembly is mountedin a gle -see Fig. 3--which is arrangedto simulate-theconditions within the mechanism for. which the assemblyis designed, including mounting the arbor or stafi between jewelbearings as used in clock and like mechanisms.

Thejig is provided with two bearing blocks 24 having bearings zfi suchasjewel bearings in which the balance wheel I0 is pivotally mounted on itsstaff [2. The blocks 24 are arranged in a known mannerso that they maybe loosened .to allow the staff-to be placedbetween the bearingsand-then secured to form rigid bearings in which the stafi may rotatefreely.

One end of the spring I4 is anchored to the staff I! by the collet .18or the like in the known manner and the other and 301s passed succesthe-spring and are constructed to form the equivalent to the like device ina clock or like mechanism. (Fig.1). The block 34 is split to provide-aslotof 'sufilcient size that the end of the: spring Mqpasses freelythrough it without I allowing. anymplay. Thus the effective length thestaff by acollet Wand its-free end is f xed;.

to thefraine ofv the mechanismon whichthe escapement is mounted, Thefree end-of the spring 14 is usually passed through a slot or. the likeon the frame and is secured by a wedge or the like. When the balancewheel and hairspring assembly is calibrated with a constant time base,the spring is usually marked as by a scratchor kink for example, so thatwhen mountedin the frame the mark is brought into register with the edgeof the slot or the like and thus the-assemblylis mounted withthe-desired length of hairspring. j-.

- An arm I8 is pivotally mounted by a pin on of the spring, when theassembly is in the jig.

is from the collect It to the point of entry into the block 34.

As""willbe' explained later the spring i4 is "arranged in the jig withits free end 30 held higher than "the-'collet 16. This differs from "themounting of the assembly in'the clock or like mechanism :where the coilsof the spring -lie in the same'horizontal plane. Thus in the jigthe-bearing or. curb pins 32 are arranged "nearer than'in the'clock orlike mechanism to compensate for this difference.

" The roller '35 is an idler roller and is frictionally engaged by theroller 38 which is socuredto a shaft lib-mounted in the jig andconnectedpreferably directly to a low-geared electricimotor 42. Theshaft 40 is either pivoted ,magnets 44, ,fed by an alternating currentof a suitable frequency, are arranged in the jig it, so that as thewheel oscillates and thelsp'ring winds up or unwinds, it will present avarying depth in side elevation.

A projector 46 of any isuitableihnqwn conf struction is providedandfarran'ged in tlrie jig to project a light. beam across the gs ring oposite the projector-46, a photo electric. cell, 48, 1

of any suitable known construction, is' arlfa lged so that thelight-beamirom theprojector'will cast the shadow oi"; the spring Illthereon, As will be seen from Fig.4 thef li'ght beam is projected acrossa chordof the' spring angl isf so positioned that, when the spring is'unwound it will lie across the light beam 4 lf 1dWhenwound amount ofbeam covered and uncovered by "the oscillating spring isimmaterialpit isthevarif ation in the light falling on the photo';elec tric cell whichis important and the cell and associated members of the apparatus willbe adjusted to ensure that the light variation on the cell is recordedand compared with-the constant time base. a H

In Fig. 3 the light beam is shown asbeing in the direction of the arrowIso that its path lies along the lower edges of the springncoils. As thespring unwinds and winds up the coils will lie respectively more orlesson the beam. The directions of the beam shown inFigs'. ,3 and 4 maybe combinedif desired.

The cell 48 is connected electrically to any amplifier 58 of suitableknown construction. The output of the amplifier is connected to anelectro-magnetic relay A (Fig. .5). whichisfitted with a number ofcontact pairs. to be described. When the relay A is energised it will,close, among other electric circuits as described later, the

first contact pair 5| being the supply circuits,

of the shaded pole. electro-magnets 44.. If, the

balance wheel ID is caused to swing clockwise; and reverse, thehair-spring M will, in one. ,.di--

rection wind up close and the opposite direction will unwind and cause.a variation in they quantity of light reaching the photo-electric cell43. The lower and'upper peal oi thisvariation will exactly coincide-ineach swing with one or other of the directions of-movement' of thebalance wheel. I The amplifier 5ll coupled to the photo-electriccell-48, is:so adjusted that it will deliver an electric-impulse .to thev,relay A either when the maximum or, as, it may be more convenient,when the minimum quantity of light will reach thephoto-electric cell.This impulse is so delayed that it should close the circuit of therotating field generating electro;

magnetic system to the electric magnets 44, when the balance wheelIll-has already turned almost half of its swing in one direction; itwill be seen from the above description, that if the balance wheel hasbeenv caused to startv up it will be clear of the,.be am.fThe actual.

6 startoperating instantaneously when its circuit at astandby point isclosed. The origin of the required constant time beat may be -'a highfrequency crystal oscillator or frequency standard (not shown)connectedto a series of multivibrators. The filament of every valve isconnected to themain supply in order to maintain theheating ofthecathodes. Along the chain of the multi-vibrator stages one of thegrid supply (in a position where the possible time error is negligible)is partially suppressed or interrupted through a circuit governed bythesecond pair of contacts 52 fitted on relay A. The-operation of th'etimefb ase generator is such,'therefore, that it may be started at anytime when thephoto-electric cell controlled relay A opcrates at the peakof the swing of the self-' sc atin a ne he l The outputof the time-basegenerator 54 is connected to a relay B. The relay' B is constructed sotha'tits"operatingperiod is the same asthat of the relay A and the relayB is fitted with a holding c0i1 56, which holding coil when energisediwl l maintain, the circuit established by the coritactpairs of the relayv The holding coil 56' of the relay B receives its main supply throughthe third contact pair 69. ottherelay A which is a .circuit breakingcontact pair, meaning that it'will break the circuit of the holding coil56 of the relay B every time the relay A operates. A three positioncontrol switch 62 is proyidedg the wiring diagram'iFig. 5) indicates howI are connected together,

In its first position the switch '62 disconnects the light source 'inorder to prevent the photocell operating relay A and thus enable the jigtobe loaded. j

In the second position the switch 62 connects the tin e-base generatorto a relay C instead of to the relay B and connects the relay C to therotating field operatingTcoils and finally connects the time, beatsource into; theoperating circuit.

' In the third position, the switch 62 will cancel the condition ofvarious circuits established in thesecond position, andreeestablish thecircuits as in its first-positionfandfwill also connect up the lamp inthe projector.

One contact pair 58 ofthr'elay B is capable ofclosing the circuit ojfthe" electric motor 42, which as above described, is capable of turningthe rollers 36, 33, Preferably, the hair-spring subject to timing, isalwaystoo'long and it is to be shortened to obtain a correct time beat.Therefore, the time 'space'betwee'n two beats of the self-oscillatingbalance wheel is longer than one identical impulse received' fromthe-con stant time beat source. 4

Referring to Fig.2; in the jg'raph'shown, the ordinatesrepresents theamount'of light'received by the cell; from the light source whentraversing the oscillating spring 'andthe impulse of the time-basegenerator; the abscissae represent the time values of the oscillationsof spring and con' stant time base. The curve 64 is that of a hairspringand is inifact a sine 'curve; The curve 66-=is that ofthetime-basegenerator orv a sawtoothed generator; g; T

At the point X in th'e curVe 64 the spring is approaching thecentre ofits oscillation represented by the point Ytkthe next double oscillationor cycle of spring oscillation is completed at. the point Z. The'curve66 starts at point R corresponding to point X on curve 64 and representshe above described; components atlases,-

to, a-rat. t e t msta t at t et me b se is fullyoperational atthe point,Y; The standard time value is represented on the abscissae 1 by thelength, S.- -S minus 3-H; This-distance isinitiallyJessthan ;Y- Zsince'the spring I4 is orig: a ly-r v rl nsth n: t e po i and t dtt u lten th-3+ The operation 'of, the,above described apparatus willnowber-giyen from which. it will be seen that U vthe above. adjustment or the,length 1 of I the spring M is; achieved automatically: and l rapidly. IV

To;10ad; lth e,ii g the switch 62;will be ,turned'to the first position.When thejig is fullyloaded d-(theai -s rins J l c d w -the. rollers36,;3 8 the switch 52 will be turned tothe second ;po sition Thetime-base, generator will art; a dth ush t e r a ,0 @Will d l veimpulses to therotatingfield generating. electronets, 4 ter l-a few m use reb an heel 4. w l be n tozsw a dw n ts o i la eqnr sufi cientlyr-seatt hi -a ma k variation of theheightorthe hair-spring in the path tlsb b am e ad u in p a n. is istartedbyniovingr the switch 62 to itsthird position. i

In the .thirdposition the ,switohifil, ,as, it ,is

described previously, will switch, onthe,lamp in el oiecto ws t at,helphotore ric -ce.11 ma re ister ,the first pealt of the oscillatingnovement of thebalance-wheel hair-springassemblyh The relay A willoperate and will maintain closed the rcireuit of the self-oscillatingdrive, i. e. the

electro-magnets fl, (and the grid circuit of the r time-base generator,and at. thesame timewill openthecoil circuit of the relay B.

Thetime-base generator will operate. and its,

first impulse will be a certain time lag earlier than the second impulseof the relay A (see Fig-r2}? The relay :B qWill therefore operate andwill;

B ,will be repeated automatically until; both-relays pe a e hron ly.

A -furthe r;-pair;of; contacts 68 :may be added to the relay A and therelay' Bfwhich may be n ectedzln s ie er h. a h r. l y.- elay D; circuitso; that when the; tworelays A and B operate synchronously i. e. ;inidentical time, the relay Dwill beenfirgizedto cutoff; the light sourceand; the-apparatus, and; also signalling by any, suitable :meansthat-the objects "of timing havebeen achieved,

It-wlll: be understood that anysuitable prime mover maybe-usedinplaceof-theelectric motor 42 providing it can be operated-in the abovedescribed (manner 1 within the desired limits of timeand. rotation oftheshaft 40.

While-the.electromagnets M are quite suitable=r-and-satisfactory inoperation, any other known suitable means suchas magnets operated -10,nextipoint Ron, curve 65 the motor 42 is operatedto-rreduce-theaefiectiye length of thespr-ing 14..

8,.- by 3-phase supply-may; be provided for oscillatingthe balanoewheeland hair-spring assembly.

Further-the light source is shown as the projector 46, but anyotherknown suitable source or lightpmay be employed.

The invention has been described with reference to balance wheel and.hair-spring assemblies for use in clock, watch and like mechanisms butit may also be used for adjusting such assemblies for use in otherdevices such as stroboscopic. devices. In the'last named devices theassemblymay be used not as a constantly oscillatingmechanism, but as afloating mechanisin which, when subjected to the forces orcharacteristlcs to be measured, will record these forcesas a measurementof the spring displacement, on a .dial or the like over which moves apointeror arm connected to the arbor or stafi of the balance wheel. Inthis case, it is still the length of the spring which is important andmust be adjusted initially to the correct length, In such a constructionthe constant timebeat source is replaced by a calibrated standard ofspring displacement.

I claim: 7

An apparatus for automatically adjusting a balance wheel and hair-springassembly adapted for use in time-pieces and the like, in which theassembly is mounted in a manner simulating the conditions within themechanism wherein the assembly is to be used, comprising:electricalmeans for maintaining the balance wheel ina state ofcontinuous self-oscillation throughout the adjustment; means under thecontrol of the balance wheel for producing electrical wheel pulses of afrequency corresponding to that of the self-oscillations of the balancewheel; an electrical time-base generator producing standard pulses atpredetermined intervals of time; means under the control of the saidelectrical wheel pulses adaptedto'initiate the starting of eachtime-base operation of the said generator; an electric motor adapted torotate only when there is a time discrepancy between thewheelzpulses-and the standard pulses of the balance wheel and time-basegenerator respectively and to stop when the said discrepancy is reducedto zero; and means between the electric motor vand the hairspringcapable of eilecting a shortening -movement of --the hairspring underthe control of the electric motor the latter means comprising aroller-secured-to the-motor shaft and another roller,-between which tworollers lies the outerend of the hair spring in frictional contacttherewith, whereby the shortening of the hair spring is effectedgradually by the electric motor as the discrepancy interval betweenthe-wheel pulses and the standard pulses is reduced-and the furthershortening of the hairspring stops when the said discrepancy intervalhas been reduced to zero and the electric motor stops,

LASZLQ NEMENYI-KATZ.

REFERENCES CITED The following references are of record in the file ofthis patent-:-

UNIIED STATES PATENTS Number Name Date 2,094,057 Brown Sept. 28, 19372,227,858 Knobel Jan. 7, 1941 2,330,416 Gibbs, Sept. 28, 1943

